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Jack D. Ade, Jamie A. Harley and Paul S. Bradley

Purpose:

To quantify the physiological responses, time–motion characteristics, and reproducibility of various speed-endurance-production (SEP) and speed-endurance-maintenance (SEM) drills.

Methods:

Sixteen elite male youth soccer players completed 4 drills: SEP 1 v 1 small-sided game (SSG), SEP running drill, SEM 2 v 2 SSG, and SEM running drill. Heart-rate response, blood lactate concentration, subjective rating of perceived exertion (RPE), and time–motion characteristics were recorded for each drill.

Results:

The SEP and SEM running drills elicited greater (P < .05) heart-rate responses, blood lactate concentrations, and RPE than the respective SSGs (ES 1.1–1.4 and 1.0–3.2). Players covered less (P < .01) total distance and high-intensity distance in the SEP and SEM SSGs than in the respective running drills (ES 6.0–22.1 and 3.0–18.4). Greater distances (P < .01) were covered in high to maximum acceleration/deceleration bands during the SEP and SEM SSGs than the respective running drills (ES 2.6–4.6 and 2.3–4.8). The SEP SSG and generic running protocols produced greater (P < .05) blood lactate concentrations than the respective SEM protocols (ES 1.2–1.7). Small to moderate test–retest variability was observed for heart-rate response (CV 0.9–1.9%), RPE (CV 2.9–5.7%), and blood lactate concentration (CV 9.9–14.4%); moderate to large test–retest variability was observed for high-intensity-running parameters (CV > 11.3%) and the majority of accelerations/deceleration distances (CV > 9.8%) for each drill.

Conclusions:

The data demonstrate the potential to tax the anaerobic energy system to different extents using speed-endurance SSGs and that SSGs elicit greater acceleration/deceleration load than generic running drills.

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Marianne Lacharité-Lemieux and Isabelle J. Dionne

Chronic effects of two different exercise environments on self-chosen intensity and physiological adaptations were examined in postmenopausal women. Twenty-three healthy to overweight (body mass index [BMI] 22–29 kg/m2) postmenopausal women performed three weekly training sessions during 12 weeks and were assigned to either: (1) indoor training or (2) outdoor training. Body composition, metabolic profile, and physical fitness (including Vo2max, maximal strength, and endurance) were assessed pre- and postintervention. Exercise intensity was measured every week during the training. Maximum intensity decreased significantly in time only in outdoor training (p ≤ .05). Body composition and VO2max were significantly improved indoors (p ≤ .05), whereas resting blood pressure and upper body maximal strength and endurance were improved outdoors (p ≤ .05). Indoor training is associated with maintaining intensity over time and slightly higher physiological improvements than outdoor training. However, outdoor training seems promising from a long-term perspective, due to its positive effects on health parameters and exercise adherence.

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Daniel L. Blessing, Robert E. Keith, Henry N. Williford, Marjean E. Blessing and Jeff A. Barksdale

The purpose of this study was to determine the effects of an endurance training program on blood lipids and lipoproteins in adolescents. Fifteen males and 10 females, ages 13 to 18 years, underwent pretest evaluations, including physical measurements, nutritional intake, physical working capacity (PWC), and fasting serum lipid and lipoprotein levels. Physical conditioning consisted of a 16-week progressive endurance training (ET) program 40 min·day1 three times per week. Twenty-five males and females matched for age, sex, and race served as controls. Following the conditioning program, the ET group had a significant increase (p < .05) in PWC and a significant decrease (p < .05) in sum of skinfolds and resting heart rate. A significant decrease (p < .05) was also noted for total cholesterol (TC) and the ratio of TC to high density lipoprotein cholesterol (HDL-C) with a significant increase (p < .05) in HDL-C. No differences were found for the control group. The results suggest that 16 weeks of endurance training favorably improves blood lipid profiles in adolescents.

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Jeffrey E. Herrick, Judith A. Flohr, Davis L. Wenos and Michael J. Saunders

Purpose:

This study compared the metabolic and performance effects of riding front-only suspension (FS) and front-and-rear suspension (FRS) mountain bicycles on an off-road course that simulated competitive cross-country race conditions (>105 min in duration, with ∼70% of time spent riding uphill).

Methods:

Seven competitive mountain bikers (73.8 ± 7.6 kg; 61.0 ± 4.3 mL·kg–1·min–1) completed two randomized FS and FRS trials. Bikes were similar, excluding rear wheel suspension on the FRS, which increased bike weight by ∼2 kg. Each trial consisted of four laps of rugged 8 km trail with 154 m of elevation gain per lap. The first three laps were performed at ∼70% of VO2max; VO2, HR, and RPE were collected during the first and third laps. The final lap was performed as a maximal time-trial effort.

Results:

During the first and third laps, VO2, HR, and RPE were similar between FS and FRS. However, FS was significantly faster than FRS during the ascending segment of the course (17.6 ± 2.9 vs 18.9 ± 3.4 min, P = .035), despite similar VO2 (P = .651). Although not statistically significant, FRS tended to be faster than FS during the descending portion of the course (8.1 ± 2.0 vs 9.1 ± 2.1, P = .067) at similar VO2. Performance during the final time-trial lap was significantly faster for FS than FRS (24.9 ± 3.9 min, 27.5 ± 4.9 min, P = .008).

Conclusion:

FS was faster than FRS over a course that simulated competitive cross-country race conditions. The faster times were likely the result of improved cycling economy during ascending, which were at least partially influenced by the lighter weight of the FS.

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George T. Hardison Jr., Richard G. Israel and Grant W. Somes

The purpose of this study was to identify the most desirable cranking rate to be used by paraplegic individuals during submaximal arm training programs. Eleven healthy paraplegic males (M age = 28.8 years) with lesion levels ranging from T4 to T12 served as subjects. Arm exercise loads for the four submaximal cranking rates studied (50, 60, 70, and 80 rpm) were set to elicit 60% of peak V̇O2. Duration of the submaximal tests was 15 min. V̇E, V̇O2, RER, HR, and differentiated RPE were recorded each minute throughout the 15-min test. A randomized block ANOVA and Duncan’s post hoc analysis indicated that 80 rpm produced significantly higher (p <.05) values for HR, absolute V̇O2, V̇E, V̇CO2, and V̇E/V̇O2 than any other rates. Cranking at 70 rpm resulted in significantly higher (p <.05) values for O2 pulse, while relative V̇O2 was significantly higher (p <05) at 70 rpm than at all other rates except 80 rpm. RPE was significantly higher (p <.05) at 50 rpm than at 60 or 70 rpm, with no difference between 50 and 80 or 60, 70, and 80. The authors concluded that 70 rpm was the most appropriate cranking rate for paraplegic males to use during arm training programs.

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Stephen F. Figoni, Richard A. Boileau, Benjamin H. Massey and Joseph R. Larsen

The purpose of this study was to compare quadriplegic and able-bodied men on selected cardiovascular and metabolic responses to arm-crank ergometry at the same rate of oxygen consumption (V̇O2). Subjects included 11 untrained, spinal cord-injured, C5–C7 complete quadriplegic men and 11 untrained, able-bodied men of similar age (27 years), height (177 cm), and mass (65 kg). Measurement techniques included open-circuit spirometry, impedance cardiography, and electrocardiography. Compared with the able-bodied group, at the V̇O2 of 0.5 L/min, the quadriplegics displayed a significantly higher mean heart rate and arteriovenous O2 difference, lower stroke volume and cardiac output, and similar myocardial contractility. These results suggest that quadriplegic men achieve an exercise-induced V̇O2 of 0.5 L/min through different central cardiovascular adjustments than do able-bodied men. Quadriplegics deliver less O2 from the heart toward the tissues but extract more O2 from the blood. Tachycardia may contribute to low cardiac preload and low stroke volume, while paradoxically tending to compensate for low stroke volume by minimizing reduction of cardiac output.

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Shona L. Halson, Marc J. Quod, David T. Martin, Andrew S. Gardner, Tammie R. Ebert and Paul B. Laursen

Cold water immersion (CWI) has become a popular means of enhancing recovery from various forms of exercise. However, there is minimal scientific information on the physiological effects of CWI following cycling in the heat.

Purpose:

To examine the safety and acute thermoregulatory, cardiovascular, metabolic, endocrine, and inflammatory responses to CWI following cycling in the heat.

Methods:

Eleven male endurance trained cyclists completed two simulated ~40-min time trials at 34.3 ± 1.1°C. All subjects completed both a CWI trial (11.5°C for 60 s repeated three times) and a control condition (CONT; passive recovery in 24.2 ± 1.8°C) in a randomized cross-over design. Capillary blood samples were assayed for lactate, glucose, pH, and blood gases. Venous blood samples were assayed for catecholamines, cortisol, testosterone, creatine kinase, C-reactive protein, IL-6, and IGF-1 on 7 of the 11 subjects. Heart rate (HR), rectal (Tre), and skin temperatures (Tsk) were measured throughout recovery.

Results:

CWI elicited a significantly lower HR (CWI: Δ116 ± 9 bpm vs. CONT: Δ106 ± 4 bpm; P = .02), Tre (CWI: Δ1.99 ± 0.50°C vs. CONT: Δ1.49 ± 0.50°C; P = .01) and Tsk. However, all other measures were not significantly different between conditions. All participants subjectively reported enhanced sensations of recovery following CWI.

Conclusion:

CWI did not result in hypothermia and can be considered safe following high intensity cycling in the heat, using the above protocol. CWI significantly reduced heart rate and core temperature; however, all other metabolic and endocrine markers were not affected by CWI.

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Stephen Hill-Haas, Greg Rowsell, Aaron Coutts and Brian Dawson

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John Kenny, SarahJane Cullen and Giles D. Warrington

Purpose:

“Ice-mile” swimming presents significant physiological challenges and potential safety issues, but few data are available. This study examined deep body temperature (BT), respiratory rate (RR), and swim performance in 2 swimmers completing an ice-mile swim of 1 mile (1600 m) in water less than 5°C.

Methods:

Two male cold-water-habituated swimmers completed a 1-mile lake swim in 3.9°C water. For comparative purposes, they completed an indoor 1-mile swim in 28.1°C water. The Equivital physiological monitoring system was used to record BT and RR before, during, and after each swim. Total time to complete the swims and 400-m splits were recorded.

Results:

One swimmer became hypothermic after 27 min while swimming, reaching BT of 33.7°C at swim’s end. On exiting the water the swimmers experienced large BT after-drops of –3.6°C and –2.4°C, reaching low points of 33.2°C and 31.3°C 38 and 23 min postswim, respectively. Respiratory rate and swim pace decreased over the course of the ice-mile swim for both swimmers. Swim pace for 1 swimmer declined sharply in the final 400-m lap of the ice mile when he was hypothermic. Both swimmers remained hypothermic 60 min postswim (34.2°C and 33.4°C).

Conclusion:

Ice-mile swimmers may become hypothermic while swimming, and the postswim BT after drop may expose them to dangerous levels of hypothermia. Pace and RR should be monitored as proxies for a swimmer’s physiological state. Postswim recovery should also be monitored for hypothermia for at least 1 h.

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Helmi Chaabène, Emerson Franchini, Bianca Miarka, Mohamed Amin Selmi, Bessem Mkaouer and Karim Chamari

Purpose:

The aim of this study was to measure and compare physiological and time–motion variables during karate fighting and to assess eventual differences between winners and defeated elite karatekas in an ecologically valid environment.

Methods:

Fourteen elite male karatekas who regularly participated in national and international events took part in a national-level competition.

Results:

There were no significant differences between winners and defeated karatekas regarding all the studied variables. Karatekas used more upper-limb (76.19%) than lower-limb techniques (23.80%). The kisami-zuki represented the most frequent technique, with 29.1% of all used techniques. The duration of each fighting activity ranged from <1 s to 5 s, with 83.8% ± 12.0% of the actions lasting less than 2 s. Karatekas executed 17 ± 7 high-intensity actions per fight, which corresponded to ~6 high-intensity actions per min. Action-to-rest ratio was about 1:1.5, and high-intensityaction- to-rest ratio was ~1:10. The mean blood lactate response at 3 min postcombat (Lapost) elicited during karate fighting was 11.18 ± 2.21 mmol/L (difference between Lapre and Lapost = 10.01 ± 1.81 mmol/L). Mean heart rate (HR) was 177 ± 14 beats/min (91% ± 5% of HRpeak). Karatekas spent 65% of the time exercising at HR >90% of the individual HRpeak.

Conclusion:

Karatekas predominantly use upper-limb karate techniques. Karate’s nature is intermittent, with fighting activities representing ~6% of total combat’s duration and ~84% of actions lasting less than 2 s, with ~21-s mean time interval in between. Kumite combat sessions induced high La and near-maximal cardiovascular strain. Other key success factors should be investigated to properly discriminate winners and defeated athletes.